The study, carried out by the Bahamas National Trust, suggests that Jhau plantation in sand dunes is the wrong choice
Over the last three decades, the government has been planting Jhau (Casuarina equisetifolia) trees along the southeastern coastline as part of a coastal afforestation initiative.
The evidence however, raises questions as to whether the plants are indeed helpful in protecting the coasts or are in fact harming the sand dunes.
In the last three years, Jhaus have been planted over 258 hectares along the coastline under a project titled Climate Resilient Participatory Afforestation and Reforestation Project (CRPARP).
Of this, 183 hectares falls under Cox’s Bazar, said Md Humayun Kabir, divisional forest officer of Chittagong Coastal Forest Division.
The objective of jhau plantation along the coast, the project document says, is to have these plants “function as wind break and combat tidal surges.”
But official data suggests that the trees themselves are vulnerable to tidal surges and high winds.
Cox’s Bazar Divisional Forest Officer Ali Kabir informed the Dhaka Tribune that though the Forest Department planted around 294 hectares of Jhau at different times, currently there is only 190 hectares of Jhau left, and the rest of it has been destroyed in cyclones and tidal surges.
Dhaka University botany Professor Dr Mohammad Zashim Uddin told the Dhaka Tribune, “Usually, sand dunes are the natural barriers against coastal surges. Jhau or Casuarina is a plant that prevents the growth of the dunes.”
In the Bahamas, an island state in the West Atlantic Ocean, a study has shown that the Jhaus are harmful to the coasts as they are uprooted by the first hit of cyclones due to their thick and shallow roots.
The study, carried out by the Bahamas National Trust, suggests that Jhau plantation in sand dunes is the wrong choice.
Unlike native shrubbery, the thick shallow roots of the Jhau make it much more susceptible to high winds, leading to increased beach and dune erosion and interference with nesting activities of sea turtles there, the study says.
Even in Bangladesh, Jhau tree is not a natural vegetation for the sand dunes, a senior forest official with long experience in coastal afforestation told the Dhaka Tribune.
“When the trees are planted in any sand dune and they grow, it stops the natural growth of the sandy beach which is raised gradually as sand comes in with the waves,” the official said.
“Therefore, the growth of the sand dunes, which is the natural embankment to protect against tidal surges, has stopped and made the coasts vulnerable,” the official added.
Asked about negative impacts of Jhau, CRPARP project Director Uttam Kumar Saha said: “Look, we have been planting the Jhau trees in the coast since 1990s, but we did not have seen any negative impact.”
The CRPARP project, worth US$33.8 million, was sanctioned under the Bangladesh Climate Change Resilience Fund (BCCRF) in 2013.
The $190 million fund was established in 2012 with contributions from development partners including Australia, Sweden, Switzerland, UK and USA for adaptation measures to tackle adverse impacts of climate change.
Of the fund, $22 million goes to afforestation and reforestation programmes implemented by the Forest Department.
Under the programme, a total of 17,000 hectares along the 1,672km coast was supposed to be covered with plantation.
Of that, Jhau would have been planted on 410 hectares of coastal sand dunes. However, finally the project achieved a target of 258 hectares.